package com.zyj.java1;

import java.io.FileNotFoundException;

/**
 * @program: JVMDemo
 * @ClassName CustomerClassLoader
 * @author: YaJun
 * @Date: 2021 - 12 - 02 - 11:50
 * @Package: com.zyj.java1
 * @Description: 用户自定义加载器
 */
public class CustomerClassLoader extends ClassLoader {

    @Override
    protected Class<?> findClass(String name) throws ClassNotFoundException {

        try {
            byte[] result = getClassFromCustomPath(name);
            if (result == null) {
                throw new FileNotFoundException();
            } else {
                return defineClass(name, result, 0, result.length);
            }
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
        throw new ClassNotFoundException(name);
    }

    private byte[] getClassFromCustomPath(String name) {
        // 从自定义路径中加载指定类：细节略
        // 如果指定路径的字节码文件进行了加密，则需要在此方法中进行解密操作。

        return null;
    }

    public static void main(String[] args) {
        try {
            CustomerClassLoader customerClassLoader = new CustomerClassLoader();
            Class<?> clazz = Class.forName("One", true, customerClassLoader);
            Object obj = clazz.newInstance();
            System.out.println(obj.getClass().getClassLoader());
        } catch (Exception e) {
            e.printStackTrace();
        }
    }


}
